Furnace for heat treatment of metal



April 14, 1925. 1,533,491

G. F. WRIGHT ET AL.

FURNACE FOR HEAT TREATMENT OF' METAL Filed JuTy 23, 1923 Patented Apr.14, 1925.

UNITED STATES PATENT OFFICE.

GEORGEF. WRIGHT AND ALBERT S. KNAFP, OF WORCESTER, MASSACHUSETTS, AS-SIG'NORS TO G. F. WRIGHT STEEL z; WIRE COMPANY, OF 1WORCESTER, MASSA-CHUSETTS, A CORPORATION OF IVEASSACHUSETTS.v

FURNACE FOR HEAT TREATMENT OF METAL.

`Application `filed July 23, 1923. Serial No. 653,238.

To all whom, it may concer/a.'

Be it known thatwe, GEORGE F. VRIGHT and ALBERT S. KNAPP, both citizensof the United States, residing at lVorcester, in

the county of lorcester and Commonwealth of Massachusetts, have inventeda new and useful Improvement 1n a Furnace forHeat Treatment of Metal, ofwhich the following, together with the accompanying drawings, is aspecification.

Our invention relates generally to furnaces for the heat treatment 'ofmetal and has to do particularly with furnaces adapted for thecontinuous annealing of material, such as wire, rods or bars, by thepassage of the same through the furnace.

Furnaces of this type, as heretofore constructed, have usually provideda number of continuous passages formed in an arch of lire brick, orother refractory material, the arch being so arranged in the furnacethat the products of combustion can vpass under and over the same. Inorder to obtain the desired length of passages for the material, thearch usually consists of a number of transverse rows of bricks, eachbrick having an opening extending therethrough, with the openings inadjacent bricks of different rows, in alinement. The above describedfurnace construction possesses several disadvantages from a practicalstandpoint, arising from the fact that `tire brick, or other similarrefractory material, is a. poor conductor of heat, and bricks areditlicult to keep in alineinent. It has been found that when the bricks`are iliade heavy enough for the arch to possess considerable structuralstrength, a great deal `of fuel is required in order to heat thematerial passing through the furnace to the desired temperature,whereas, when the thickness of the bricks is reduced to obtain betterheat conduction to the material, then the bricks are liable to be burnedout. lVhen this occurs, the entire top of the furnace must be removed inorder to repair the arch, and such repairs are ditlicult to make owingto the fact that all the bricks in the furnace niust always be in properalinement toprovide continuous passages for the material.

According to the present invention we propose to provide an improvedfurnace for heat treatment of metal, 'which involves a adicallydifferent construction of the arch kthrough which the material ispassed.

Briefly stated, our invention contemplates `the construction of the archof the furnace of a number of multi-apertured units ofv cast iron orsteel, each unit being an integral arch in itself, and having itsseveral passages lined up with the corresponding passages of adjacentarch units. Our improved arch' construction is therefore adapted toreadily conduct heat to the material under treatment, in addition topossessing certain y the line 2-2 of Fig. l.

Fig. 3 is a horizontal sectional view along the lineB-S of Fig. 2,looking in the direction of the arrows. n

Fig. Il is a sectional view on an enlarged scale of one of the archunits and a portion of another, showing the dovetailing of the flanges,the arch units being removed from the furnace.

Fig; 5 is a perspective view of a portion of one unit shown in Fig. fi.

Like reference characters refer to like parts in the different figures.

,teferring to Fig. l, the furnace generally consists of side` walls 1 ofn'iasonry, cach providing an abutment 2 for supporting the sides of ourimproved arch construction indicated generally at 3. The top of thefurnace is indicated at t, and in operation of the furnace, the burninggases pass both below and above the arch construction 3, as indicated byarrows in Fig. 2. The particular arrangement.` of the masonry supiporting and surrouijiding the arch 3, and the manner of subjecting 'thesaine to heat, forms no part of the present invention, and any suitablearrangement of thesey parts can be employed without departing from ourinvention.

As best shown in Figs. 2 to 5 inclusive, the arch 3 consists of a numberof similar units 5 of cast iron or steel, each unit being an arch `initself and extending between the abutinents 2 of the side walls. 1. Eacharch unit 5 is provided with a ru'unber of parallel ,passages Gextending longitiidinallyK therethrough, the passages 6 of one unitlining up with the passages Grof the next ad jacent unit, as indicatedclearly in Fig. 21. ln this Way, a number of parallel passages areprovided extending the entire length of the arch structure, and it isvobvious that the number of arch units 5 may be varied in order toprovide any desired length ofpassages, through Which themetalv undertreat# ment is to; be passed. l, l

As best shoiyn ,in Figs. 4 and 45, each arch unit 5 is provided at one`end with continuous parallel `flanges or lips 'i' overhanging the endsof 'the passages G, While the j other endy of the unit is providedWitliseats 8. extendingv allieve and below` the passages G for receivingthe flanges 7 of the next adjacent arch unit 5. The seats 8 are ofsubstantiallyuthe saine form as the flanges i', so that whenthe fianges7 of one unit 'are-in engagement With the seats 8 of the next adjacentunit, the units are in interlocking relation, and the points at whichthe passages il of one unit joinl the passages of another "unit aresubstantially sealed against the entrance of the products of'co'mbnstion, during the operation lof the furnace. y

Each of the arch units 5 can beplaced in position in the.' furnace bymoving the same endnise While resting atits sides on the abutments 2,and it is obvious that the several units can be readily assembled, withthe passages G all in al'in'enienn by reason of the interlockingrelation betWeen'the abuting material far more efficiently t ting endsy.of adjacent `vunits. In' case. it should be desired to replace anyoneofthe arch units 5, itis. only necessary touremore one end Wall of thefurnace and 'Withdraw the arch units 5 endrvise until the unit whichk itis 'desired ,to replace, is reached. |The units can lthen be reassembledby inserting them cndwise in thc furnace, ythe entire operation beingcarried ont Without disturbing the side walls Vi or top Alfof the Whenthe furnace isin opelation, it is apparent that the heat of ythc burninggases will be readily conducted to the .material in the passages 6, byreason of the fact that the entirek arch structure 3 is composed oi"metal of high conductivity, as compared to fire brick or otherrefractorymaterial. For this reason, a furnace embodying our iin-`/roved arch constrnctionis capablcof heat- |`han furnaces constructedof fire brick. ln addition, our improved furnace is extremely rugged inconstruction, by reason ofthe fact that each arch unit 5 is entirelylself-supporting, and being in'ade of Ym'etal, is inherently strongerthan any arch built 'up of masonry. The unitary construction of the archsections also lends itself to ease of assembly 'or disassembly, aspreviously pointed out. Owing to the more condensed construction of themetalA arch, as co1npared With iire brick, the cross section of thefurnace may be materially reduced, thus loweringthe cost and decreasingthe surface exposed to external radiation.

We claim, l

1. A furnace for the heat treatment of metal, comprising a castingprovided with longitudinal passages for the reception of the materialunder treatment. l ,A

2. A fu"n`ace for the vheat treatment of metal, comprising a ui'iitarymember ex# tending across theV furnace land p'row'fid'ed with aplurality of longitudinal passages. A- furnace for the heat treatment.of metal, cinprising' a metallic arch-shaped men'ib'er provided 1aitli aplurality of spaced longitudinal passages. I

4. A furnace for the heat treatment of metal, comprising a main furnaceinclosurc, and an arch-shaped casting spanning 'said inclovsure anddividing it into two heat chambers, said casting provided `With aplurality of .longitudinal passages. n

5. yA furi'iace for the heat treatment of metal, comprising van archstructure con# sisting of a number of sin'iilar arch-shaped unitsarranged end t'o "end and each pro-- Yide'd with a plurality oflongitudinal passages. f l

6. furnace for the heat treatment of metal, comprising a main furnaceinclbsure and' `an arch structure spanning said inclosure, dividing itinto 'two heat chambers, said arch -structure lconsisting of a number ofarch units each vprovided with longitudinal passages, the vsaid. unitsbeing airranged 'end to end Withthe passages of one unit :registeringwith the lpas-'sages 'of the next adjacent unit.

7. A furnace for the heat treatment of. metal, comprising an archstructure consisting ot' ar number-of arch kunits arranged cndfto `end,each ofs'aid arch units having a plurality of longitudinal passages, andeach of saidarch units having'coacting, projecting "and r recessedportions for the yalincnient of one unit to the next unit-and to joinythe said passages so that their longitudinal axes coincide in the samestraight lines.

8.]A furnace for the heat treatment ot metal, comprising an archstructure consisting of a number of arch units cach haring longitudinalpassages I"extending therethrough', the said Vunits being arranged end'to end with cori'rcsj'nonding Irecess and projecting vportions ofadjacent units in-eng'ageniient.

Grenen r. ,Water-ir.

ALBERT S. KNPP.

